RNA is the functional entity expressed from the genome of all human cells. Accordingly, specific RNA molecules such as messenger RNAs (mRNA) are responsible for protein synthesis, whereas different types of noncoding (nc) RNAs are known to associate with proteins to form ribonucleoprotein (RNP) complexes. It is now clear that errors during the synthesis and processing of RNA, as well as during RNP assembly do occur in cells, but are largely prevented by poorly characterized quality control mechanisms. The proposed research program will make use of two innovative and complementary experimental systems to characterize important RNA quality control pathways. The proposed research is of significance, as errors during RNA synthesis and RNP assembly could result in mutant and possibly deleterious proteins and RNPs, which are known to contribute to cancer biology.